Can be the right thing to do—if it's not a red sauce. Pesto, oil-"sauces", that kind of thing.

That probably wouldn't be described as "inedible" then.

It was red sauce. Anything other than red sauce is too fancy for my parents.

My wife and I always heat the pesto a little in the pan - is that not the right thing to do?

Pesto burns really easily and its flavors after cooking are generally regarded as worse than when it's uncooked. Heating it a little probably doesn't hurt, but it's intended to be kind of a fresh sauce, so, little or no cooking. Doesn't come through as well with the jar stuff vs. home-made, but still.

I got through college on this, it actually wasn't that bad. I added little sauce (Most expensive part of the dish! I didn't buy cheap sauce.) and folded it into the boiling hot noodles immediately after draining. Brought the whole dish almost immediately to serving temperature, so I could eat right away instead of waiting for it to cool.

You should really check out /r/shittyfoodporn if you want to see just how much you can take.